Conventional cargo carrying vehicles and shipping containers have swing-out cargo doors that include a latch assembly. The typical latch assembly, shown in FIG. 1 and designated generally by reference numeral 10, comprises a vertical locking bar 12 and a horizontally extending latch arm 14 pivotally attached to the vertical bar. The vertical locking bar 12 includes a locking cam (not shown) that engages a corresponding keeper (not shown) in the frame surrounding the cargo door 16 when the door is closed and the latch arm 14 is in a position parallel with the door. The locking cam is disengaged from the keeper when the locking arm is rotated to a position perpendicular to the cargo door allowing the door to be opened.
As shown in FIG. 1, the latch arm 14 of the latch assembly 10 is secured in a horizontal position parallel to the cargo door 16 by a hasp assembly 20. The hasp assembly 20 includes first and second hasps 24 and 26 mounted on a base plate 28. The base plate 28 is fixed to a back plate 30 that is bolted to the door 16. The first or lower hasp 24 is stationary to receive and support the latch arm 14 as it is pivoted into the engaged or latched position horizontally, as shown in FIG. 1. The second or upper hasp 26 is pivotally connected to the base plate 28 and back plate 30 to rotate within a plane generally parallel to the cargo door 16. The ends of the first and second hasps 24 and 26 are provided with aligned holes (not numbered) for receiving the shackle of a padlock (not shown) for securing the latch arm 14 within the hasp assembly 20 and preventing the cargo door 14 from being opened.
Where access to the cargo is to be limited, such as when the cargo comprises foods, chemicals, hazardous wastes, or the like, a tamper-evident security seal 34, such as a ribbon seal, a padlock seal, a cable seal, or the like, is installed through the aligned hasp holes. These seals are commercially available and typically are embossed with serial numbers. The serial number of the seal may be included on the bill of lading or shipping papers by the shipper. Upon delivery, the recipient can verify the integrity of the cargo by checking the serial number of the intact seal on the cargo door with the serial number on the billing of lading. If the seal is broken or bears a different number, the recipient may, and usually does, refuse delivery.
However, because the security seal 34 is exposed to the environment during shipment, it is vulnerable to accidental damage and to malicious damage by vandals when the cargo carrying vehicle or shipping container is left unattended. Consequently, even if no tampering or theft of the cargo occurs, the integrity of the cargo may be questioned on delivery if the seal is no longer intact. This results in unnecessary expense to the shipper and the owner of the cargo, as well as delay and inconvenience to the recipient.